perf tools: Fix backslash processing on trace print formats

The handling of backslashes was broken. It would stop parsing
when encountering one. Also, '\n', '\t', '\r' and '\\' were not
converted.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <20091014194357.521974680@goodmis.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

tools/perf/util/trace-event-parse.c

@@ -522,7 +522,10 @@ static enum event_type __read_token(char **tok)
 			last_ch = ch;
 			ch = __read_char();
 			buf[i++] = ch;
-		} while (ch != quote_ch && last_ch != '\\');
+			/* the '\' '\' will cancel itself */
+			if (ch == '\\' && last_ch == '\\')
+				last_ch = 0;
+		} while (ch != quote_ch || last_ch == '\\');
 		/* remove the last quote */
 		i--;
 		goto out;
@@ -2325,7 +2328,27 @@ static void pretty_print(void *data, int size, struct event *event)
 
 	for (; *ptr; ptr++) {
 		ls = 0;
-		if (*ptr == '%') {
+		if (*ptr == '\\') {
+			ptr++;
+			switch (*ptr) {
+			case 'n':
+				printf("\n");
+				break;
+			case 't':
+				printf("\t");
+				break;
+			case 'r':
+				printf("\r");
+				break;
+			case '\\':
+				printf("\\");
+				break;
+			default:
+				printf("%c", *ptr);
+				break;
+			}
+
+		} else if (*ptr == '%') {
 			saveptr = ptr;
 			show_func = 0;
  cont_process: